refactor!: move NotProvided/NotProvidedType to Core (remove from Options)

NotProvidedType and NotProvided are now defined and exported ONLY from
CTBase.Core as the canonical ecosystem-wide sentinel. They are removed
from CTBase.Options (no re-export): Options.NotProvided / Options.NotProvidedType
no longer exist.

- Options/not_provided.jl renamed to not_stored.jl (keeps NotStored only).
- Internal Options/extraction + option_definition reference Core.NotProvidedType.
- Tests repointed to Core.NotProvided.

BREAKING: replace Options.NotProvided -> Core.NotProvided.
Bump 0.25.0-beta.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ocots

BREAKINGS.md

@@ -2,6 +2,30 @@
 
 This document outlines all breaking changes introduced in CTBase v0.18.0-beta compared to v0.17.4. Use this guide to migrate your code and understand the impact of these changes.
 
+## Breaking changes (0.25.0-beta)
+
+- **`NotProvided` / `NotProvidedType` removed from `CTBase.Options`.** They now live and are
+  exported **only** in `CTBase.Core`. `CTBase.Options.NotProvided` and
+  `CTBase.Options.NotProvidedType` no longer exist, and `using CTBase.Options` no longer
+  brings these names into scope.
+
+  **Migration:** replace `Options.NotProvided` → `Core.NotProvided` and
+  `Options.NotProvidedType` → `Core.NotProvidedType` (fully qualified: `CTBase.Core.NotProvided`).
+
+  ```julia
+  # before
+  using CTBase.Options
+  OptionDefinition(name=:x, type=Int, default=NotProvided)
+
+  # after
+  import CTBase.Core
+  using CTBase.Options
+  OptionDefinition(name=:x, type=Int, default=Core.NotProvided)
+  ```
+
+- `NotStored` / `NotStoredType` are unchanged and remain extraction-internal to
+  `CTBase.Options` (the defining file was renamed `not_provided.jl` → `not_stored.jl`).
+
 ## Non-breaking note (0.24.0-beta)
 
 - **Differentiation module**: Added comprehensive AD backend infrastructure for computing gradients

CHANGELOGS.md

@@ -5,6 +5,23 @@ All notable changes to CTBase will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.25.0-beta] - 2026-06-26
+
+### ⚠️ Breaking Changes
+
+- **NotProvided moved to Core (no re-export)**: `NotProvidedType` and `NotProvided` are now
+  defined and exported **only** from `CTBase.Core`. They are **no longer available** from
+  `CTBase.Options` — `CTBase.Options.NotProvided` / `CTBase.Options.NotProvidedType` no longer
+  exist. Replace any `Options.NotProvided` usage with `Core.NotProvided` (or
+  `CTBase.Core.NotProvided`).
+- `CTBase.Core.NotProvided` is the canonical ecosystem-wide "not provided" sentinel.
+
+### 🔄 Refactoring
+
+- `CTBase.Options` now only defines the extraction-internal `NotStored` / `NotStoredType`
+  sentinels (file renamed `not_provided.jl` → `not_stored.jl`). Internal Options/Strategies
+  code references `Core.NotProvidedType` directly.
+
 ## [0.24.0-beta] - 2026-06-25
 
 ### ✨ New Features

Project.toml

@@ -1,6 +1,6 @@
 name = "CTBase"
 uuid = "54762871-cc72-4466-b8e8-f6c8b58076cd"
-version = "0.24.0-beta"
+version = "0.25.0-beta"
 authors = ["Olivier Cots <olivier.cots@irit.fr>", "Jean-Baptiste Caillau <caillau@univ-cotedazur.fr>"]
 
 [deps]

src/Core/Core.jl

@@ -13,6 +13,7 @@ import DocStringExtensions: TYPEDEF, TYPEDSIGNATURES
 include("types.jl")
 include("tags.jl")
 include("caches.jl")
+include("not_provided.jl")
 include("default.jl")
 
 # Private utilities
@@ -27,6 +28,7 @@ include("display.jl")
 # Export public API
 export ctNumber, matrix2vec, to_out_of_place, make_coerce, @ensure
 export AbstractTag, AbstractCache
+export NotProvided, NotProvidedType
 export Style, Palette
 export DEFAULT_PALETTE, MONOCHROME_PALETTE, HIGH_CONTRAST_PALETTE
 export current_palette, set_palette!, set_color!, reset_palette!, show_palette

src/Core/not_provided.jl

@@ -0,0 +1,39 @@
+"""
+$(TYPEDEF)
+
+Singleton type marking the absence of a provided value.
+
+Ecosystem-wide sentinel for "no default / argument not given". The canonical
+value is [`NotProvided`](@ref).
+
+See also: [`NotProvided`](@ref).
+"""
+struct NotProvidedType end
+
+"""
+    NotProvided
+
+Singleton instance of [`NotProvidedType`](@ref).
+
+The canonical "not provided" sentinel used across the control-toolbox ecosystem
+(option defaults, optional variable parameters, optional AD backends, …).
+
+# Example
+```julia-repl
+julia> using CTBase.Core
+
+julia> x = NotProvided
+NotProvided
+
+julia> x isa NotProvidedType
+true
+
+julia> x === NotProvided
+true
+```
+
+See also: [`NotProvidedType`](@ref).
+"""
+const NotProvided = NotProvidedType()
+
+Base.show(io::IO, ::NotProvidedType) = print(io, "NotProvided")

src/Options/Options.jl

@@ -18,14 +18,13 @@ import CTBase.Core
 import CTBase.Exceptions
 
 # Submodules
-include(joinpath(@__DIR__, "not_provided.jl"))
+include(joinpath(@__DIR__, "not_stored.jl"))
 include(joinpath(@__DIR__, "option_value.jl"))
 include(joinpath(@__DIR__, "option_definition.jl"))
 include(joinpath(@__DIR__, "extraction.jl"))
 
 # Public API
 
-export NotProvided, NotProvidedType
 export OptionValue, OptionDefinition, extract_option, extract_options, extract_raw_options
 export all_names, aliases
 export is_user, is_default, is_computed  # is_computed works for both OptionValue and OptionDefinition

src/Options/extraction.jl

@@ -77,7 +77,7 @@ function extract_option(kwargs::NamedTuple, def::OptionDefinition)
     end
 
     # Not found - check if default is NotProvided
-    if def.default isa NotProvidedType
+    if def.default isa Core.NotProvidedType
         # No default and not provided by user - return NotStored to signal "don't store"
         return NotStored, kwargs
     end
@@ -223,7 +223,7 @@ builders to use their own defaults. Options with explicit `nothing` values are i
 opts = (backend = OptionValue(:optimized, :user), 
         show_time = OptionValue(false, :default),
         minimize = OptionValue(nothing, :default),
-        optional = OptionValue(NotProvided, :default))
+        optional = OptionValue(CTBase.Core.NotProvided, :default))
 
 extract_raw_options(opts)
 # (backend = :optimized, show_time = false, minimize = nothing)
@@ -236,7 +236,7 @@ function extract_raw_options(options::NamedTuple)
     for (k, v) in pairs(options)
         val = v isa OptionValue ? v.value : v
         # Filter out NotProvided values, but keep nothing values
-        if !(val isa NotProvidedType)
+        if !(val isa Core.NotProvidedType)
             raw_opts_dict[k] = val
         end
     end

src/Options/not_provided.jl

@@ -0,0 +1,30 @@
+"""
+$(TYPEDEF)
+
+Internal sentinel type used by the option extraction system to signal that an option
+should not be stored in the instance.
+
+This is returned by `extract_option` when an option has [`CTBase.Core.NotProvided`](@ref)
+as its default and was not provided by the user.
+
+# Note
+This type is internal to the Options module and should not be used directly by users.
+Use [`CTBase.Core.NotProvided`](@ref) instead.
+
+See also: [`CTBase.Core.NotProvided`](@ref), [`extract_option`](@ref).
+"""
+struct NotStoredType end
+
+"""
+    NotStored
+
+Internal singleton instance of [`NotStoredType`](@ref).
+
+Used internally by the option extraction system to signal that an option should not
+be stored. This is distinct from `nothing` which is a valid option value.
+
+See also: [`CTBase.Core.NotProvided`](@ref), [`extract_option`](@ref).
+"""
+const NotStored = NotStoredType()
+
+Base.show(io::IO, ::NotStoredType) = print(io, "NotStored")

src/Options/not_stored.jl

@@ -85,7 +85,7 @@ struct OptionDefinition{T}
         computed::Bool=false,
     ) where {T}
         # Validate with custom validator if provided (skip for NotProvided)
-        if validator !== nothing && !(default isa NotProvidedType)
+        if validator !== nothing && !(default isa Core.NotProvidedType)
             try
                 validator(default)
             catch e
@@ -152,7 +152,7 @@ julia> # No default - creates NotProvidedType
 julia> def3 = OptionDefinition(
            name = :input_file,
            type = String,
-           default = NotProvided,
+           default = CTBase.Core.NotProvided,
            description = "Input file path"
        )
 OptionDefinition{NotProvidedType}(...)
@@ -270,7 +270,7 @@ julia> using CTBase.Options
 julia> def = _construct_option_definition(
            :input_file,
            String,
-           NotProvided,
+           CTBase.Core.NotProvided,
            "Input file path",
            (:input,)
        )
@@ -285,13 +285,13 @@ See also: `OptionDefinition`, `NotProvided`, `is_required`
 function _construct_option_definition(
     name::Symbol,
     type::Type,
-    default::NotProvidedType,
+    default::Core.NotProvidedType,
     description::String,
     aliases::Tuple{Vararg{Symbol}},
     validator::Union{Function,Nothing},
     computed::Bool,
 )
-    return OptionDefinition{NotProvidedType}(;
+    return OptionDefinition{Core.NotProvidedType}(;
         name=name,
         type=type,
         default=default,
@@ -543,7 +543,7 @@ Returns `true` when the default value is `NotProvided`.
 ```julia-repl
 julia> using CTBase.Options
 
-julia> def = OptionDefinition(name=:input, type=String, default=NotProvided,
+julia> def = OptionDefinition(name=:input, type=String, default=CTBase.Core.NotProvided,
                           description="Input file")
 OptionDefinition{NotProvidedType}(...)
 
@@ -553,7 +553,7 @@ true
 
 See also: `has_default`, `default`
 """
-is_required(def::OptionDefinition) = def.default isa NotProvidedType
+is_required(def::OptionDefinition) = def.default isa Core.NotProvidedType
 
 """
 $(TYPEDSIGNATURES)
@@ -579,7 +579,7 @@ true
 
 See also: `is_required`, `default`
 """
-has_default(def::OptionDefinition) = !(def.default isa NotProvidedType)
+has_default(def::OptionDefinition) = !(def.default isa Core.NotProvidedType)
 
 """
 $(TYPEDSIGNATURES)